| 1 | //===----------------------------------------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | |
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| 10 | // Assumption: minValue < maxValue |
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| 11 | // Assumption: minValue <= rhs <= maxValue |
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| 12 | // Assumption: minValue <= lhs <= maxValue |
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| 13 | // Assumption: minValue >= 0 |
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| 14 | template <typename T, T minValue, T maxValue> |
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| 15 | constexpr T euclidian_addition(T rhs, T lhs) { |
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| 16 | const T modulus = maxValue - minValue + 1; |
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| 17 | T ret = rhs + lhs; |
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| 18 | if (ret > maxValue) |
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| 19 | ret -= modulus; |
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| 20 | return ret; |
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| 21 | } |
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| 22 | |
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| 23 | // Assumption: minValue < maxValue |
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| 24 | // Assumption: minValue <= rhs <= maxValue |
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| 25 | // Assumption: minValue <= lhs <= maxValue |
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| 26 | // Assumption: minValue >= 0 |
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| 27 | template <typename T, T minValue, T maxValue> |
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| 28 | constexpr T euclidian_subtraction(T lhs, T rhs) { |
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| 29 | const T modulus = maxValue - minValue + 1; |
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| 30 | T ret = lhs - rhs; |
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| 31 | if (ret < minValue) |
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| 32 | ret += modulus; |
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| 33 | if (ret > maxValue) // this can happen if T is unsigned |
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| 34 | ret += modulus; |
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| 35 | return ret; |
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| 36 | } |
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| 37 | |
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